Promising therapy for neurological condition cautiously welcomed

Pharma News: Around one-third of people with epilepsy in Australia cannot control their seizures with currently available anti-epileptic drugs. For the first time, a potentially curative drug will undergo a clinical trial for this patient cohort.

In Australia, there are over 20 anti-epileptic drugs and 3.1 million prescriptions* dispensed for antiepileptic medicines that reduce seizure frequency in ~70% of patients. When considering alternatives to pharmacological treatment in drug-resistant epilepsy, several neurostimulation modalities are available – either invasive, requiring a surgical procedure to implant the device, or non-invasive, with no permanent device implantation required. Unfortunately, there are a lack of guidelines or general consensus across epilepsy centres on when and how to use non-pharmacological treatments.

In a new study led by Dr Pablo Casillas-Espinosa and Professor Terry O’Brien from Monash Neuroscience and the Alfred reveal the potential for sodium selenate to become the first medical disease-modifying therapy for epilepsy.

According to Dr Casillas-Espinosa, current therapies target symptoms only.

“So when a patient stops or misses the medication they are as likely to have a seizure as if they had been untreated, and importantly one-third of patients don’t respond to any treatments so far,” he said.

The study conducted in animal models showed sodium selenate to have a long-lasting effect (after months of stopping the medication) in reducing the frequency of seizures and in 30% of cases stopping them altogether. It also improved other aspects of epilepsy such as memory, learning and sensor-motor functioning.

On the strength of these findings, the researchers have been awarded a $3 million Medical Research Future Fund (MRFF) grant to start a clinical trial of sodium selenate as a curative treatment in patients with drug-resistant epilepsy.

The Epilepsy Foundation cautiously welcomed the news. Graeme Shears, CEO of Epilepsy Foundation, said “This is very exciting news and gives hope to people impacted by an epilepsy diagnosis that there may be a better option for management of seizures in the future. However, while sodium selenate is seeing positive results in rodents, the side-effects and benefits in humans are, as yet, unknown.

“The Epilepsy Foundation welcomes and encourages all new trials as there are currently 250,000 people living with epilepsy in Australia with approximately 30% who do not respond to current anti-seizure treatments and who continue to have ongoing, often debilitating, seizures. 

“The drug is at first clinical trial stage which, if proven, will be an effective treatment for people with drug-resistant temporal lobe epilepsy, which is a common form of focal epilepsy.

“In the last 50 years, we have had over 20 new drugs and the rate of seizure freedom has not changed. So, while encouraging, it is still early days.”

The first-in-human trial is due to start in October and will investigate the effect of 6 months of treatment with sodium selenate in patients with drug-resistant temporal lobe epilepsy (TLE). 124 patients will be enrolled across at least 9 sites nationwide over 2.5 years.

According to Professor O’Brien, epilepsy is one of the most common and serious disabling brain disorders which is costly to both individuals and their families, as well as the national health budget with an estimated annual economic cost in Australia of $12.3 billion.

“Despite the cost of the disease – and the enormous amount of research into it, there has not been a single therapy developed to prevent the development of epilepsy, nor to mitigate its severity once established. Until now,” he said.

“This Phase 2 clinical trial, if effective, has the potential to tackle a disease that is an enormous global burden as well as being truly transformative for people who are impacted by often daily seizures, with no respite.”

The new study uses the DOOR scale, adapted for use in the trial by a focus group of people with epilepsy. The group from multiple states across Australia developed the scale according to the outcomes most important to them when trialling a new treatment for epilepsy.

“The scale we will be using is totally different to what we had initially planned. The consumer group were fantastic for helping us better understand their priorities when it comes to introducing a new medication into their lives,” said Dr Lucy Vivash, lead scientist on the upcoming trial.

“It absolutely shows the importance and benefit of involving patients in the planning of trials and research.”

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*According to AIHW data, Sanofi’s Valproate was the most commonly dispensed antiepileptic medication (24% of all prescriptions filled) followed by UCB’s Keppra (22%) which has several generic options. Around 388,000 people were dispensed at least one antiepileptic medication during 2019–20, with an average of 8 prescriptions dispensed per person.

In May 2021, cannabidiol was made available through the PBS for patients with severe myoclonic epilepsy in infancy (SMEI), also known as Dravet Syndrome. Cannabidiol can only be prescribed in the first instance by a treating neurologist, and must only be prescribed as an adjunctive therapy once the condition has proven to be poorly controlled by at least two epilepsy medications.